Optical Transport Network (OTN), a core technology of a next generation transport network, includes technical specifications for electrical layer and optical layer. The OTN possesses a remarkable Operation, Administration and Maintenance (OAM) capability, a strong Tandem Connection Monitoring (TCM) capability, and a Forward Error Correction (FEC) capability. OTN is able to operate and manage a high volume traffic and has already become a mainstream technology for the backbone transport network.
In terms of service processing capability, OTN provides a strong capability in multi-service accessing. With the rapid development of data service, more and more Ethernet services are transported over OTN. Moreover, in a technical transition from Ethernet to telecommunication level, OTN is required to transparently transport Ethernet client service at a full rate to the utmost extent.
As a core technology of the next generation Ethernet, 100GE (100G Ethernet, a high-speed Ethernet) will become a primary interface to core routers. The 100GE may include multiple physical layer (PHY) interface devices at 10×10G, 5×20G and 4×25G, or may include a single PHY interface at 1×100G. The above mentioned multi-lane PHY 100GE interface may become the prevailing form for interfaces of 100GE at present.
Since it is difficult for a physical coding sublayer (PCS) of the multi-lane PHY 100GE interfaces to accomplish a virtual concatenation (VC)-like function of a transport network hierarchy, problems such as how to realize a multi-lane PHY 100GE in the OTN so as to transparently transmit the Ethernet client service at a full bit rate and how to eliminate the time delay occurred when multi-lane PHY 100GE interface traverses the OTN need to be addressed immediately.
In the prior art, a traditional method for transporting multi-lane PHY 100G Ethernet client service is a method of Medium Access Control (MAC) transparent transport. Specifically, 100GE MAC frames are extracted from the received multi-lane PHY 100G Ethernet client service. Then, the extracted MAC frames are adapted in accordance with a Generic Frame Protocol (GFP). A corresponding transport lane (e.g., Virtual Concatenation frame OPU2-11v which is 11 times the size of OPU2; Virtual Concatenation frame OPU1e-10v which is 10 times the size of OPU1E; Virtual Concatenation frame OPU2e-10v which is 10 times the size of OPU2E; or Virtual Concatenation frame OPU3-3v which is 3 times the size of OPU3) in OTN is selected to transmit the adapted MAC frames.
It is discovered that the method for transporting multi-lane PHY 100G Ethernet Client service has the following defects in the prior art. 100GE transparent transport at full bit rate cannot be achieved (i.e., the method in the prior art does not support the transport of private application information at PCS layer). Moreover, this method requires rearranging and splitting multiple lanes of 100GE client server signals, which increases the device complexity and cost.
In the prior art, a method for transporting multi-lane PHY 100G Ethernet client service is described below. Since a single multi-lane PHY signal among the multi-lane PHY 100G Ethernet signals may be transported independently with transparency, multiple transport lanes at 10G, 20G or 25G level (e.g., OPU2/OPU1e/OPU2e, OPU2-2v/OPU1e-2v/OPU1e-2v, or OPU2-3v/OPU1e-3v/OPU1e-3v) in OTN are selected accordingly and each single multi-lane PHY signal included in the multi-lane PHY signals of the 100G Ethernet client service is mapped into multiple independent transport lanes. The multiple independent transport lanes transport each single multi-lane PHY signal, respectively. After receiving the data, a receiving side recovers the single multi-lane PHY signal which is transmitted over each independent transport lane.
It is discovered that the method for transporting multi-lane PHY 100G Ethernet Client service in the prior art has the following defects. Since the transmission lanes of each independent transport lane are different, it is impossible to control the time delay for each independent transport lane. This would cause the actual delay of the 100G Ethernet client service signal to exceed the delay time acceptable by the 100GE multiple PHY interfaces, and eventually make the receiving party unable to recover the 100G Ethernet client service signal. Meanwhile, the frequency deviation of the client signals required by this method does not meet the IEEE definition of Ethernet interface.